Keychain Secure Notes missing after Big Sur upgrade

Hi,

After a clean install of Big Sur from Mojave and using Time Machine to migrate user data, my Keychain data was moved to the desktop into a folder called 'relocated items.nosync'.

I managed to open some data from this folder in Big Sur Keychain but I believe it only relates to System keychain rather than any secure notes.

Is there a way to get them back or is the only option to downgrade to Mojave and use time machine to recover everything?

Or, could I use any of the data in the time machine backup to connect to another mac running mojave to load the secure notes in keychain?

Thanks

Jason

Mac Pro Late 2013.